Symptoms - HVAC Systems - Manual. Chevrolet PJJ 2000

For 1990-2009 cars

Important: The following steps must be completed before using the symptom tables.

1. Perform the Diagnostic System Check - HVAC Systems - Manual before using the Symptom Tables in order to verify that all of the following are true:

• | There are no DTCs set.

• | The control module(s) can communicate via the serial data link.

2. Review the circuit description in order to familiarize yourself with the system functions. Refer to HVAC Blower Controls Circuit Description and HVAC Compressor Controls Circuit Description .

### Visual/Physical Inspection

• | Inspect for aftermarket devices which could affect the operation of the HVAC System. Refer to Checking Aftermarket Accessories in Wiring Systems.

• | Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

### Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

### Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:

• | Blower Motor Inoperative at Any Speed

• | Blower Motor Operates at High Speed Only

• | Air Recirculation Inoperative

• | Air Recirculation Always On

• | Cooling Insufficient - Air Conditioning (A/C) System

• | Defrosting Insufficient

• | Heating Insufficient

• | Heat Excessive

• | Air Delivery Improper

• | Noise Diagnosis

• | Odor Diagnosis

• | Heater Blower Controls System Check